It is known that on-axis chromatic aberration occurs in an image captured via a normal optical system. A technique for correcting such on-axis chromatic aberration by means of image processing has been proposed (for example, see Patent Literature 1).
With this technique, a near-saturated region having pixels that exceed a saturation threshold and candidate regions having pixels in which blue and red intensity values of the pixels considerably exceed green intensity values of the pixels are found, and the candidate regions that are adjacent to the near-saturated region are detected as on-axis-chromatic-aberration regions.